Insulated container and liner

ABSTRACT

A portable soft sided insulated container has an impermeable liner that provides a liquid holding barrier. The liner is folded from a single monolithic plastic sheet to reduce or eliminate the need for heat welded seams. The liner seats within the container and has a releasable attachment around its lip for mating with the rim of the container. The container has an insulated lid so that the entire assembly may be closed. The liner can be removed for cleaning, or replacement if punctured. When not in use the entire assembly can be folded into a collapsed position for storage.

BACKGROUND OF THE INVENTION

[0001] Field of the Invention

[0002] This invention relates to the field of soft sided insulatedcontainers. In particular it relates to soft sided insulated containershaving removable impermeable liners for discouraging or preventing theleakage of liquids.

[0003] In recent times soft sided insulated containers have becomepopular for carrying either articles that may best be served cool, suchas beverages or salads, or warm, such as appetizers, hot dogs, and soon. Such containers are frequently used to carry liquids, whether hotliquids, such as soup containers, coffee or tea, or cold liquids such asbeer pop, juices and milk. The containers are typically made in agenerally cube like shape, whether of sides of equal length or not,having a base, four upstanding walls, and a top. The top is generally alid which opens to permit articles to be placed in, or retrieved from,the container.

[0004] By the nature of their use, it is advantageous for the containersto be water tight. That is, whether to hold melted run-off from icecubes or to hold spilled liquids, the container must be sufficientlyliquid tight that it does not leave a trail of drips, or become moist orsticky to the touch of a person carrying the container.

[0005] The present inventor has found it disadvantageous to try to sealthe container itself. The type of insulating wall used by the presentinventor is generally sewn at its seams. Sewn seams have a tendency toleak at the stitches. Another approach is to fold the insulated blanketfrom which the container is made, to present an assembly that, throughfolding, has no seams. This is also disadvantageous, in the presentinventor's view, because the insulated blanket used to form thecontainer walls is relatively thick. The thick material does not foldwell, in the inventor's view. It would be preferable to form animpermeable layer that has a relatively thin wall thickness so that theresulting product does not look bulky and cumbersome.

[0006] It is also advantageous to be able to clean the inside of theinsulated container. Spilt liquids may not always have the mostattractive air when allowed to dry, and may cause the inside of thecontainer to become unsightly. It is possible to provide a plastic linerfor soft sided insulated containers. A see through plastic liner can bemade of the minimum amount of material by using only a single layer, andforming seams where the edges of the material meet. A common method offorming such a seam is to weld two adjacent edges together by heating.However, an existing liner of this type is known to have had a tendencyfor the heat welded seams to develop leaks over time. It would beadvantageous to reduce or eliminate the number of heat welded seamsformed in areas of the liner that may need to be water tight.

[0007] In general, manufacture of an assembly of this type emphasizescost reduction. One common source of cost savings is a reduction of theraw material used. However, the present inventor has observed,counter-intuitively, that the overall benefit an increase in rawmaterial use can outweigh the cost saving that would otherwise beachieved. Unexpectedly, the use of a greater amount of material in afolded assembly has been found to be advantageous, and has eliminatedthe need to have a heat welding station in manufacture.

SUMMARY OF THE INVENTION

[0008] In an aspect of the invention there is a soft-sided insulatedcontainer, and a removable liner for placement inside the container. Theliner is folded from a monolithic sheet of liner stock to define achamber, capable of holding liquids. The liner is free of heat weldedseams.

[0009] In another feature of that aspect of the invention the liner ismade from a water impermeable plastic sheet. In an additional feature ofthat aspect of the invention the liner is made from a translucent staticcling vinyl sheet. In another additional feature of that aspect of theinvention the soft sided insulated container has a base, sides and atop. The liner has a base, sides for placement inside and adjacent tothe base and sides of the container. The top of the container ismoveable to an open position to permit articles to be placed in thechamber.

[0010] In still another additional feature of that aspect of theinvention the chamber has an opening, the opening having a lip, and theliner is mated to the cooler about the lip. In yet another additionalfeature of that aspect of the invention the opening has four sides, thelip extends about the four sides opening and the liner is mated to thecontainer on the four sides. In a further additional feature of thataspect of the invention the liner has a rectangular base and four sidesextending from the base, each of the sides having an edge adjoining thebase and a distal edge distant from the base. The chamber has an openingdefined between the distal edges of the sides.

[0011] In a still further additional feature of that aspect of theinvention one of the sides has a lid member extending therefrom, the lidmember being moveable to close the opening of the liner. In yet anotheradditional feature of that aspect of the invention the lid member is aflap formed integrally with the liner, the flap having four lid edges,one edge being a folded hinge edge adjoining one of the distal edges ofthe sides, the remaining three lid edges having a closure for matingwith the remaining three distal edges.

[0012] In another aspect of the invention there is a removable liner forplacement inside the container. The liner is formed from a waterimpermeable plastic sheet. The sheet has a periphery. The liner has aquadrilateral base and four sides extending from the base to define achamber therebetween capable of holding water. Each of the sides arejoined to the base at a base edge. Each of the sides has a pair oflateral edges each meeting the base edge at a corner. Each of the sideshas an edge opposed to the base edge and meets each of the lateral edgesat a corner. The sheet has corner portions defined between adjacentlateral edges of two of the sides and the periphery and the cornerpositions are folded to lie against the sides.

[0013] In a further additional feature of that aspect of the inventionthe base is a rectangle and two of the sides, joined to the base onopposite sides of the rectangle, are trapezoidal. In a still furtheradditional feature of that aspect of the invention the chamber has theshape of an inverted, truncated rectangular based pyramid. In yetanother additional feature of that aspect of the invention the containerhas an internal face made from a reflective material and the liner istransparent.

[0014] In another aspect of the invention there is a soft sidedinsulated container, and a removable liner for placement inside thecontainer. The liner is formed from a water impermeable plastic sheet.The sheet has a periphery. The liner has a rectangular base and foursides extending from the base to form a chamber therebetween, each ofthe sides being joined to the base at a base edge. The sheet is foldedon a first pair of parallel fold lines to define one pair of the baseedges. The sheet is folded on a second pair of fold lines to define theremainder of the edges. The sheet has four corner portions each definedbetween an end portion of one of the first pair of fold lines, anadjacent end portion of one of the second pair of fold lines and theperiphery, and the corner portions are folded to lie against the sides.

[0015] In an additional feature of that aspect of the invention thesides have an inside face and an outside face and the corner portionsare folded to lie against the outside faces. In another additionalfeature of that aspect of the invention each of the corners is folded toform a triangular flap, and each of the flaps is folded to lie againstone of the sides. In still another additional feature of that aspect ofthe invention one of the triangular flaps is folded to lie against eachof the sides of the liner. In still yet another additional feature ofthat aspect of the invention two of the triangular flaps are folded tolie against one side of the liner. In a further additional feature ofthat aspect of the invention two of the triangular flaps are folded tolie against one side of the liner, and the other two triangular flapsare folded to lie against another side of the liner.

[0016] In still a further additional feature of that aspect of theinvention each of the sides has a distal edge opposed to its respectivebase edge. The chamber has a lip defined by the distal edges. The cornerportions are fastened to the sides adjacent the lip. In still yet afurther additional feature of that aspect of the invention one of thesides has a cover flap formed integrally therewith, and joined theretoat a cover fold, the cover flap mating with the distal edges of theremaining sides of the liner. In an additional feature of that aspect ofthe invention the container has a reflective inner surface and the lineris transparent.

DESCRIPTION OF THE DRAWINGS

[0017] These aspects and other features of the invention can beunderstood by with the aid of the following illustrations of a number ofexemplary, and non-limiting, embodiments of the principles of theinvention in which:

[0018]FIG. 1 is a three quarter view, general arrangement drawing of aninsulated container and liner assembly according to the presentinvention;

[0019]FIG. 2 is a view of the liner of FIG. 1 taken on an oppositeangle;

[0020]FIG. 3 is a developed view of a liner for use in the assembly ofFIG. 1;

[0021]FIG. 4 is a developed view of an alternative liner for an assemblyanalogous to the liner of assembly of FIG. 1 in which two sides aretapered;

[0022]FIG. 5 is a developed view of an alternative liner for an assemblyanalogous to the liner of assembly of FIG. 1 in which four sides aretapered;

[0023]FIG. 6 is a developed view of an alternative liner for an assemblyanalogous to the liner of assembly of FIG. 1 in which the forward sideof the assembly is wider than the rearward side;

[0024]FIG. 7 is a front view of the assembly of FIG. 1, in a collapsedposition;

[0025]FIG. 8 is a rear view of the assembly of FIG. 1 in a collapsedposition;

[0026]FIG. 9 is a side view of the assembly of FIG. 1 in a collapsedposition;

[0027]FIG. 10; is a section showing the wall construction of theassembly of FIG. 1 and

[0028]FIG. 11 is a view of an alternative liner for the assembly of FIG.1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The description which follows, and the embodiments describedtherein, are provided by way of illustration of an example of aparticular embodiment, or examples of particular embodiments, of theprinciples of the present invention. These examples are provided for thepurposes of explanation, and not of limitation, of those principles andof the invention. In the description which follows, like parts aremarked throughout the specification and the drawings with the samerespective reference numerals. The drawings are not necessarily to scaleand in some instances proportions may have been exaggerated in ordermore clearly to depict certain features of the invention.

[0030] Referring to the general arrangement illustration of FIGS. 1 and2, an example of a preferred embodiment of an insulated container andliner assembly according to the principles of the present invention isindicated generally as 20. It has two major elements, those being anouter casing in the nature of a soft-sided insulated container 22, and aremovable, impermeable liner 24 for placement inside container 22. Anoptional moveable bulkhead, or baffle, in the nature of a partition wall25 seats within line 24 for dividing the interior space into twosub-compartments 27 and 29.

[0031] Looking at these major elements in detail, it can be seen thatcontainer 22 has a bottom 26, a front panel 28, a rear panel 30, and apair of left and right hand side panels 32 and 34. In this preferredembodiment the choice of front and rear, left and right, orientations isarbitrary. Each of front panel 28, rear panel 30, and left and righthand side panels 32 and 34 is joined at sewn seams to bottom 26 atbottom vertices 36, 37, 38, or 39 respectively. Similarly, front panel28 and side panels 32 and 34 have top edges 40, 41 and 42, distant fromtheir base edges. Rear panel 30 is joined by a folded hinge 44 at itstop edge to a top panel in the nature of a lid 46. Lid 46 has a closuremember in the nature of a zipper 48 extending in a U-shape around thethree free edge portions of its periphery to mate with the otherportions of zipper 48 positioned about the three top edges 40, 41 and 42of panels 28, 32 and 34. Lid 46 is moveable between a closed position,in which zipper 48 may be zipped closed, and an open position in whichlid 46 is folded back to permit entry and exit of objects to and from aninternal cavity 50 defined between bottom 26 and panels 28, 30, 32 and34. A generally rectangular insulated auxiliary pouch 52 is mounted tothe front face of front panel 28.

[0032] In the preferred embodiment, lid 46 has an extent substantiallyequal to that of bottom panel 26. This need not be the case. Lid 26could be a small opening set in a larger top panel, or could be anopening of half, or some other portion of the panel. The opening neednot extend fully along three sides of lid 26, but could extend alongpart of one or two sides as may be found suitable in a particular use.

[0033] Top edges 40, 41, and 42 form the rim 54 of cavity 50. On theinside of rim 54 is a liner securing means, or liner attachmentmounting, in the nature of a zipper 56, which, in the embodimentillustrated, includes portions 57, 58, and 59 mounted respectively topanels 28, 32, and 34 near their upper margins, and a hook and eyefabric fastener strip 60 mounted to panel 30. Although this arrangementis preferred, in an alternative embodiment all of strip portions 57, 58,59 and 60 (or some other combination of them) could be hook-and-eyefabric fasteners. Other types of mounting could be used, in addition tozippers, such as interlocking seal strips, snaps, clips, grommets orother means.

[0034] Container 22, with liner 24 installed, can be folded to acollapsed position, as shown in FIGS. 7, 8 and 9. In this collapsed, orstorage position, side panels 32 and 34 fold inward, and bottom 26 foldsupward. This permits front panel 28 to move toward rear panel 30. Lid 46is then drawn forward and downward in front of front panel 28 andauxiliary pouch 52. Lid 46 has, on its inner face, spaced inwardly fromzipper 48, a retainer in the nature of another hook and eye fastenerstrip 62 that engages a mating hook and eye fastener strip 64 located ona lower portion of the front face of auxiliary pouch 52. In addition,left and right hand side retainers 66 and 68 mounted to the left andright hand edges of auxiliary pouch 52 of front panel 28 are drawnaround to fasten to fastening strips 70 and 72 located on the outer,rearward face of rear panel 30. (When container 22 is in its openposition, strips 66 and 68 engage storage strips 74 and 76 located onside panels 32 and 34 respectively).

[0035] Other features of container 22 are visible in FIGS. 1 and 2.Front and rear carrying handles 78 and 80 with reinforced bails areattached to both front panel 28 and rear panel 30 to permit two peopleto carry assembly 20 between them. In the preferred embodiment assembly20 has a maximum capacity of 24 quarts. Smaller embodiments, include atwelve quart container. A single shoulder strap 79 is attached to sidepanels 32 and 34. An elasticized retaining matrix 82 permits othermaterials, such as cups, plates, serving utensils or other objects to becarried on top of assembly 20. Above strip 64, auxiliary pouch 52 has asee-through mesh pocket 84, such as may be convenient for carryingknives, forks, spoons or other objects.

[0036]FIG. 10 shows a cross section of front panel 28 with liner 24 inplace. A scab section of panel 34 is also shown to reveal its layers ofconstruction. With the exception of auxiliary pouch 52, this section istypical not only of front panel 28 but also, generally, of rear panel30, side panels 32 and 34, bottom panel 26 and lid 46. The outer facinglayer of front panel 28 is a canvas covering layer 88 for resistingabrasion. It overlays a closed cell foam insulation layer 90. The innerface of insulation layer 90 is covered by flexible plasticised metallicfoil sheeting 92 that is shiny and reflective. The material is soldunder the name Therma-Flect (T.M.). Liner 24 lies inside sheeting 92,and is pressed against it by the objects it contains. The inside ofpouch 52 is lined with white vinyl sheeting, 93 on its forward andbottom sides.

[0037] Liner 24, is shown in FIGS. 2 and 3. It is made from a membrane,or web, in the nature of a sheet 100 of flexible, transparent plasticstock, in particular, static cling vinyl. The shiny, reflective surfaceof sheeting 92 is visible through liner 24 in use. Liner 24 has a base102 and four sides, front, rear, left hand and right hand respectively,104, 106, 108, and 110 extending upwardly from base 102. Each of sides104, 106, 108 and 110 is joined to base 102 at a base edge, 112, 114,116 or 118, as indicated, and each has an opposite, distal edge 120,122, 124 or 126 distant from its respective base edge. The sides meet atrespective upstanding corners 128, 130, 132 and 134. A chamber 136 isdefined between base 102 and sides 104, 106, 108 and 110. Chamber 136has an opening 138 defined by the peripheral lip 140 formed collectivelyby the distal edges 120, 122, 124 and 126 of sides 104, 106, 108 and110. Immediately below lip 140 liner support fasteners, in the nature ofhook and eye strips, are mounted to sheet 100. This mounting may be byheat welding or by use of a bonding agent or adhesive. In the preferredembodiment lip 140 is folded over to form a hem, and fasteners 141, 144,143 are of the nature of a continuous zipper around three sides of lip140, and a fastener 142 in the nature of a fabric hook-and-eye strip aresewn in place with stitching 145 that is at a height relative to base102 that is expected to be well above the liquid level in liner 24.

[0038] In an alternate embodiment, fasteners 141, 142, and 143 are allfabric hook and eye fasteners each mounted on one side of lip 140, andwhich mate with corresponding hook-and-eye fastener strips mounted tocontainer 22. These fastener strips are commonly sold under the nameVelcro (T.M.). Optional partition 25 is variably positionable. About theupper portion of its periphery it has a strip engaging material 146 thatcatches on mating strips 147 and 148 located on the inner face of liner24. These strips can be hook and eye fastener strips. The range of thestrips permits the division of sub compartments 27 and 29 of chamber 136into equal, half-and half portions, or into some other portions, such as¼ to ¾, ⅓ to ⅔, ⅖ to ⅗ and so forth as may be found desirable given theobjects to be contained in chamber 136.

[0039] In FIG. 3 sheet 100 is shown in developed view, as it would bebefore being folded to form liner 24. A first pair of parallel foldlines 150 and 152 extend across sheet 100, and a second pair of parallelfold lines 154 and 156, perpendicular to lines 150 and 152 extend alongsheet 100, thus dividing it into nine portions within the rectangularperiphery, 158, of sheet 100. It will also be noted that each of lines150, 152, 154 and 156 has two intersections, and is thus divided into acentral sector between the parallel lines it intersects, and a pair ofend sectors between each of the parallel lines it intersects and theline's termination at periphery 158.

[0040] The central portion of sheet 100, bounded by the central sectorof each of lines 150, 152, 154 and 156, defines base 102, each of thosesectors defining one of base edges 112, 114, 116 and 118. Front side 104is defined between the central sector 160 of line 150, two parallelforward end sectors 162 and 164 of lines 154 and 156, and a mid-edgesector 166 of periphery 158. Rear side 106 is defined by the centralsector 168 of line 152, two parallel rearward end sectors 170 and 172 oflines 154 and 156, and a mid edge sector 174 of periphery 158. Left handside 108 is defined by central sector 176 of line 154, two left endsectors 178 and 180 of lines 150 and 152, and a mid-edge sector 182 ofperiphery 158. Right hand side 110 is defined by central sector 184 ofline 156, two right end sectors 186 and 188 of lines 150 and 152, and amid-edge sector 190 of periphery 158.

[0041] The remaining four portions of sheet 100 are corner portions 192,194, 196 and 198 defined by a pair of adjacent end sectors of a pair ofperpendicular lines, and a corner sector of periphery 158, indicatedrespectively as 202, 204, 206 and 208. Corner portions 192, 194, 196 and198 are bisected by diagonal bisectors 212, 214, 216 and 218 whichextend from the intersection of the respective perpendicular lines toperiphery 158.

[0042] Having thus defined the geometry of sheet 100, liner 24 is formedby folding sides 104, 106, 108 and 110 upwardly such that sectors 162and 178, 164 and 186, 170 and 180, and 172 and 186 lie adjacent to eachother to form corners 128, 130, 132 and 134 respectively. This foldingnecessitates folding of corner portions 192, 194, 196 and 198, and thisis done along their respective diagonal bisectors.

[0043] When folded along bisectors 202, 204, 206, and 208 cornerportions 192, 194, 196 and 198 form triangular flaps 220, 222, 224 and226. In the preferred embodiment flaps 220 and 222 are folded to lieagainst the outside face of front side 104, the corner of flap 220 lyingmost distant from corner 128 overlapping the corner of flap 204 lyingmost distant from corner 130. Similarly flaps 224 and 226 are folded tolie against the outside face of rear side 106 the most distant corner offlap 224 overlapping the most distant corner of flap 226. One edge ofeach flap lies roughly flush with lip 140, which is folded over and theentire periphery of opening of chamber 136 sewn as a hem 228 having adouble row of stitches. In this way liner 24 is formed from sheet 100such that it is not only free of welded seams, but free of any seamsbelow hem 228 of lip 140.

[0044] In the preferred embodiment the folding process is purelymechanical, and can be performed relatively quickly, incontradistinction to heat welding or adhesive bonding processes whichrequire a time interval for heating and cooling or for adhesive curing.Inasmuch as the preferred embodiment uses a relatively thick staticcling vinyl, sheet 100 can be folded over a cube form of the desireddimensions, and held in place by its own clinging properties inpreparation for the sewing of hem 228. The overlap of the tips of flaps202 and 204, and flaps 206 and 208, and subsequent sewing makes itdoubly improbable that liner 24 will unfold.

[0045] Liner 24 is formed from a single integral sheet, and, absentpunctures of that sheet is not intended to leak below the level of thesewn seam at lip 140. The body of base 102 and sides 104, 106, 108 and110 is seamless, being free of heat welds or other joints. In generaluse the liquid level in chamber 136 is not expected to be greater thanone half of the height of the sides, and still less commonly to be morethan three quarters of the height. There are no seams below either ofthese levels, heat welded or otherwise.

[0046] Liner 24 is also thin enough that it can be folded insidecontainer 22 when container 22 is compressed to its collapsed positionas illustrated in FIGS. 7, 8, and 9. Liner 24 need not be transparent,but could be translucent or opaque. A transparent liner is preferredsince it permits the reflection of sheeting 92 to be seen.

[0047] In an optional embodiment, a liner 224 can have its own closure,or lid, 230, to provide a double closure with lid 46 of container 22 inFIG. 11. As shown in FIG. 11, optional lid 230 extends on a foldingplastic hinge 232 that is an integral part of sheet 234 from rear side236 of sheet 234, and mates at front, left hand and right hand sideedges 238, 240 and 242 along a U-shaped closure interface such as may beheld closed by a closure member in the nature of a seal, a zipper, ahook and eye fabric fastener, or a similar device. It is not necessarythat the opening of the container, or the liner, form a parallel planeto the respective base or bottom sides. The opening could be in a skewedplane, or could be something other than a plane.

[0048] In alternative embodiments, one of each of corner flaps 220, 222,224 and 226 can be folded against each of sides 104, 106, 108 and 110,or a pair (220, 224) can be folded against left hand side 108 andanother pair (222, 226) against right hand side 110, rather than againstfront and rear sides 104 and 106 as illustrated in FIG. 11. It is notnecessary that the corner portions have one edge lying flush with lip146. However, if the corner portions are cut down, the height at which aliquid tight barrier is provided may not necessarily be as high as shownin the preferred embodiment of FIG. 1. It is also not necessary thatcorner portions 192, 194, 196, and 198 be folded against the outsidefaces of the sides, but could be folded to lie along the inside faces.It would also be possible to fold each flap to lie partially against oneside and partially against another side by using more than one fold lineand by cutting the periphery of the corner portions differently. Thereis simplicity in using a single fold and to fold the flaps against theoutside of one side of the liner, as shown in the preferred embodimentof FIG. 1.

[0049] As shown in the developed views of the alternate embodiments ofFIGS. 4, 5, and 6, the liner need not be a cube or cuboid, but could bea tapered, trapezoidal, or truncated pyramidal shape. In the embodimentof FIG. 4 a developed sheet 300 has fold lines for forming a linerhaving a pair of opposed trapezoidal sides 304 and 306 which rise atright angles from a base 308, and a pair of opposed rectangular sidesthat are folded upward at an angle corresponding to the rake angle a oftrapezoidal sides 304 and 306. It can be seen that there is one pair ofparallel fold lines 310 and 312, each line having a central sector 314,316 and a pair of left and right end sectors 318, 320 or 322, 324. Thereis also a pair of fold line sectors 326 and 328 which define theremaining two sides of base 308 (perpendicular to sectors 314 and 316).The intersections of sectors 326, 314, 328, and 316 define the cornersof base 308. Extending away from those corners to periphery 330 are leftand right hand canted trapezoidal side sectors 332, 334, 336, and 338 todefine the remaining vertices of trapezoidal sides 304 and 306. At theangular bisector of the included angle between adjacent pairs ofrectangular side lateral sectors and trapezoidal side sectors, as, forexample between sectors 318 and 332, are corner portion fold lines 340,342, 344, and 346. Corner portions 348, 350, 352 and 354, each definedbetween one trapezoidal side end sector, one rectangular side end sectorand periphery 330, have been trimmed along periphery 330 to lie flushwith the resulting lip. When sheet 300 is folded in a manner analogousto the folding of sheet 100, a cradle shaped liner will result, formating use with a similarly cradle shaped container analogous tocontainer 22.

[0050] In the embodiment of FIG. 5 a developed sheet 400 has fold linesfor forming a liner 402 having a first pair of opposed trapezoidal sides404 and 406 which rise at a non-perpendicular angle α from a base 408,and a second pair of opposed trapezoidal sides 410, 412 that are foldedupward at an angle corresponding to the vertical projection of the rakeangle β of the first pair of trapezoidal sides 404 and 406. It can beseen that there is one pair of fold line sector 414, 416 pairs of leftand right hand end sectors 418, 420 or 422, 424 and a perpendicular pairof fold line sectors 418 and 420 which define the remaining two sides ofbase 408. The intersections of sectors 418, 414, 420, and 416 define thecorners of base 408. Extending away from those corners to periphery 430are left and right hand trapezoidal side lateral sectors 422, 424, 426and 428. Similarly, left and right hand canted trapezoidal side sectors432, 434, 436, and 438 extend from those intersections toward periphery430 to define the remaining vertices of the trapezoidal sides. At theangular bisector of the included angle between adjacent pairs ofrectangular side lateral sectors and trapezoidal side sectors, as, forexample between sectors 418 and 432, are corner portion fold lines 440,442, 444, and 446 of corner portions 448, 450, 452 and 454.

[0051] Sectors 422, 424, 426, 428, 432, 434, 436 and 438 all have thesame true length, indicated as l. The distance that sectors 422, 424,426 and 428 are splayed outward from square is indicated as c.Similarly, the distance that sections 432, 434, 436 and 438 are splayedoutward from square is indicated as δ. Angle a satisfies the conditionthat Sin α=[ε/(l²−δ²)]½. Similarly Angle β satisfies the condition thatSin β=[δ/(l¹−δ²)]½.

[0052] When folded in a manner analogous to the folding of sheet 100,sheet 400 will form a truncated, inverted rectangular shaped pyramid. Itshould be noted that the pairs of opposed slanted pyramid sides need notrise at the same angle, but could be at different angles. In the mostgeneral case, each side could rise at a different angle, and to adifferent height. The upper edges of the sides need not be level, butcould have a slant, or, alternatively, need not be linear but could becurved as may suit the desired geometry. However, it is expected thatthe sides will, most often, have straight and level edges.

[0053] In the embodiment of FIG. 6, a developed sheet 500 has fold linesfor forming a liner 502 having a trapezoidal base 504 such as might bedesired in a knapsack having a large rearward face for placement againsta person's back, and a narrower outer or forward face. A pair ofparallel lines of unequal length, being a short front fold line 506 anda longer rear fold line 508, define the parallel sides of thetrapezoidal base 504. A pair of left and right hand side fold lines 510and 512 extend between lines 506 and 508 at angles to define the splayedsides of trapezoidal base 504. Front side 514, rear side 516, left side518 and right side 520 are all hinged along respective fold lines 506,508, 510 and 512 to base 504. Corner portions 522, 524, 526 and 528 aredefined between the periphery 530 and respective pairs of side sectors532 and 534, 536 and 538, 540 and 542, and 544 and 546. Each of portions522, 532, 526 and 528 has a fold line 548, 550, 552 or 554 on which therespective corner portion is folded, those portions being trimmed alongtheir peripheral edges to lie flush with the peripheral edges of therespective sides against which they are folded, similar to the mannerdescribed above in connection with the preferred embodiment.

[0054] A preferred embodiment has been described in detail and a numberof alternatives have been considered. As changes in or additions to theabove described embodiments may be made without departing from thenature, spirit or scope of the invention, the invention is not to belimited by or to those details, but only by the appended claims.

What is claimed is:
 1. A combination comprising: a soft-sided insulatedcontainer, and a removable liner for placement inside said container,said liner being folded from a monolithic sheet of liner stock to definea chamber, capable of holding liquids, said liner being free of heatwelded seams.
 2. The combination of claim 1 wherein said liner is madefrom a water impermeable plastic sheet.
 3. The combination of claim 1wherein said liner is made from a translucent static cling vinyl sheet.4. The combination of claim 1 wherein said soft sided insulatedcontainer has a base, sides and a top, said liner has a base, sides forplacement inside and adjacent to said base and sides of said container;and said top of said container is moveable to an open position to permitarticles to be placed in said chamber.
 5. The combination of claim 4wherein said chamber has an opening, said opening having a lip, and saidliner is mated to said coder about said lip.
 6. The combination of claim5 wherein said opening has four sides, said lip extends about said foursides opening; and said liner is mated to said container on said foursides.
 7. The combination of claim 1 wherein said liner has arectangular base and four sides extending from said base, each of saidsides having an edge adjoining said base and a distal edge distant fromsaid base; and said chamber has an opening defined between said distaledges of said sides.
 8. The combination of claim 7 wherein one of saidsides has a lid member extending therefrom, said lid member beingmoveable to close said opening of said liner.
 9. The combination ofclaim 8 wherein said lid member is a flap formed integrally with saidliner, said flap having four lid edges, one edge being a folded hingeedge adjoining one of said distal edges of said sides, the remainingthree lid edges having a closure for mating with the remaining threedistal edges.
 10. A combination comprising: a soft sided insulatedcontainer; and a removable liner for placement inside said container,said liner being formed from a water impermeable plastic sheet, saidsheet having a periphery; said liner having a quadrilateral base andfour sides extending from said base to define a chamber therebetweencapable of holding water; each of said sides being joined to said baseat a base edge; each of said sides having a pair of lateral edges eachmeeting said base edge at a corner; each of said sides having an edgeopposed to said base edge and meeting each of said lateral edges at acorner; said sheet having corner portions defined between (a) adjacentlateral edges of two of said sides, and (b) said periphery and saidcorner positions are folded to lie against said sides.
 11. Thecombination of claim 10 wherein said base is a rectangle and two of saidsides, joined to said base on opposite sides of said rectangle, aretrapezoidal.
 12. The combination of claim 10 wherein said chamber hasthe shape of an inverted, truncated rectangular based pyramid.
 13. Thecombination of claim 10 wherein said container has an internal face madefrom a reflective material and said liner is transparent.
 14. Acombination comprising: a soft sided insulated container, and aremovable liner for placement inside said container, said liner beingformed from a water impermeable plastic sheet; said sheet having aperiphery; said liner having a rectangular base and four sides extendingfrom said base to form a chamber therebetween, each of said sides beingjoined to said base at a base edge; said sheet being folded on a firstpair of parallel fold lines to define one pair of said base edges; saidsheet being folded on a second pair of fold lines to define theremainder of said edges; said sheet having four corner portions eachdefined between (a) an end portion of one of said first pair of foldlines; (b) an adjacent end portion of one of said second pair of foldlines, and (c) said periphery; and said corner portions are folded tolie against said sides.
 15. The combination of claim 14 wherein saidsides have an inside face and an outside face and said corner portionsare folded to lie against said outside faces.
 16. The combination ofclaim 14 wherein each of said corners is folded to form a triangularflap, and each of said flaps is folded to lie against one of said sides.17. The combination of claim 16 wherein one of said triangular flaps isfolded to lie against each of said sides of said liner.
 18. Thecombination of claim 16 wherein two of said triangular flaps are foldedto lie against one side of said liner.
 19. The combination of claim 16wherein two of said triangular flaps are folded to lie against one sideof said liner, and the other two triangular flaps are folded to lieagainst another side of said liner.
 20. The combination of claim 14wherein each of said sides has a distal edge opposed to its respectivebase edge; said chamber has a lip defined by said distal edges; and saidcorner portions are fastened to said sides adjacent said lip.
 21. Thecombination of claim 20 wherein one of said sides has a cover flapformed integrally therewith, and joined thereto at a cover fold, saidcover flap mating with the distal edges of the remaining sides of saidliner.
 22. The combination of claim 14 wherein said container has areflective inner surface and said liner is transparent.